Abstract

Increasing interests have been paid to nanofluids because of the intriguing heat transfer
enhancement performances presented by this kind of promising heat transfer media.
We produced a series of nanofluids and measured their thermal conductivities. In this
article, we discussed the measurements and the enhancements of the thermal conductivity
of a variety of nanofluids. The base fluids used included those that are most employed
heat transfer fluids, such as deionized water (DW), ethylene glycol (EG), glycerol,
silicone oil, and the binary mixture of DW and EG. Various nanoparticles (NPs) involving
Al2O3 NPs with different sizes, SiC NPs with different shapes, MgO NPs, ZnO NPs, SiO2 NPs, Fe3O4 NPs, TiO2 NPs, diamond NPs, and carbon nanotubes with different pretreatments were used as additives.
Our findings demonstrated that the thermal conductivity enhancements of nanofluids
could be influenced by multi-faceted factors including the volume fraction of the
dispersed NPs, the tested temperature, the thermal conductivity of the base fluid,
the size of the dispersed NPs, the pretreatment process, and the additives of the
fluids. The thermal transport mechanisms in nanofluids were further discussed, and
the promising approaches for optimizing the thermal conductivity of nanofluids have
been proposed.